Explain clearly why we need rain ? what are consequences of rainfall in atmosphere in world ? what are the factors for the rain cause in forests and how we need it ? describe importance of rain in geographical locations in entire wold? what is called as rain shadow effect in climate ? Which particles does form rain in air ? what is the speed of the droplets of rain in air ? how is acid rain created in nature who it is travel through clouds ? what happens when acid rain falls in buildings ?